From e520d9b6f336ead8f72d5d29ff11e1900a89222c Mon Sep 17 00:00:00 2001
From: Jan Svabenik <jan@svabi.ch>
Date: Thu, 19 Mar 2026 11:20:09 +0100
Subject: [PATCH] Fix Windows runtime DLL search for SDRplay and gpudemod

---
 build-sdrplay.ps1                           | 21 +++++++++++++++------
 internal/demod/gpudemod/gpudemod_windows.go |  3 +++
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/build-sdrplay.ps1 b/build-sdrplay.ps1
index a731d63..a884df9 100644
--- a/build-sdrplay.ps1
+++ b/build-sdrplay.ps1
@@ -12,8 +12,11 @@ $env:CC = 'gcc'
 $env:CXX = 'g++'
 
 # SDRplay
-$env:CGO_CFLAGS = '-IC:\PROGRA~1\SDRplay\API\inc'
-$env:CGO_LDFLAGS = '-LC:\PROGRA~1\SDRplay\API\x64 -lsdrplay_api'
+$sdrplayInc = 'C:\PROGRA~1\SDRplay\API\inc'
+$sdrplayBin = 'C:\PROGRA~1\SDRplay\API\x64'
+$env:CGO_CFLAGS = "-I$sdrplayInc"
+$env:CGO_LDFLAGS = "-L$sdrplayBin -lsdrplay_api"
+if (Test-Path $sdrplayBin) { $env:PATH = "$sdrplayBin;" + $env:PATH }
 
 # CUDA runtime / cuFFT
 $cudaInc = 'C:\CUDA\include'
@@ -29,11 +32,17 @@ Write-Host 'Building SDRplay + cuFFT app (Windows DLL path)...' -ForegroundColor
 go build -tags "sdrplay,cufft" ./cmd/sdrd
 if ($LASTEXITCODE -ne 0) { throw 'build failed' }
 
-$dllSrc = Join-Path $PSScriptRoot 'internal\demod\gpudemod\build\gpudemod_kernels.dll'
+$dllCandidates = @(
+  (Join-Path $PSScriptRoot 'internal\demod\gpudemod\build\gpudemod_kernels.dll'),
+  (Join-Path $PSScriptRoot 'gpudemod_kernels.dll')
+)
 $dllDst = Join-Path $PSScriptRoot 'gpudemod_kernels.dll'
-if (Test-Path $dllSrc) {
-  Copy-Item $dllSrc $dllDst -Force
-  Write-Host "Copied DLL to $dllDst" -ForegroundColor Green
+$dllSrc = $dllCandidates | Where-Object { Test-Path $_ } | Select-Object -First 1
+if ($dllSrc) {
+  if ((Resolve-Path $dllSrc).Path -ne (Resolve-Path (Split-Path $dllDst -Parent)).Path + '\gpudemod_kernels.dll') {
+    Copy-Item $dllSrc $dllDst -Force
+  }
+  Write-Host "CUDA DLL ready at $dllDst" -ForegroundColor Green
 } else {
   Write-Host 'WARNING: gpudemod_kernels.dll not found; build succeeded but runtime GPU demod will not load.' -ForegroundColor Yellow
 }
diff --git a/internal/demod/gpudemod/gpudemod_windows.go b/internal/demod/gpudemod/gpudemod_windows.go
index daae728..5e17e0b 100644
--- a/internal/demod/gpudemod/gpudemod_windows.go
+++ b/internal/demod/gpudemod/gpudemod_windows.go
@@ -136,13 +136,16 @@ func ensureDLLLoaded() error {
 				C.free(unsafe.Pointer(cp))
 				if res == 0 {
 					loadErr = nil
+					fmt.Fprintf(os.Stderr, "gpudemod: loaded DLL %s\n", p)
 					return
 				}
 				loadErr = fmt.Errorf("failed to load gpudemod DLL: %s (code %d)", p, int(res))
+				fmt.Fprintf(os.Stderr, "gpudemod: DLL load failed for %s (code %d)\n", p, int(res))
 			}
 		}
 		if loadErr == nil {
 			loadErr = errors.New("gpudemod_kernels.dll not found")
+			fmt.Fprintln(os.Stderr, "gpudemod: gpudemod_kernels.dll not found in search paths")
 		}
 	})
 	return loadErr